It is known in manufacturing to produce a material in a continuously extruded stream, feed the material out through a die that gives the material the desired shape, and cut the material to a desired size(s) as it leaves the die. In extrusion manufacturing processes, extruder die plates are often mounted to the hub, or end, of extrusion machinery.
Conventionally, the die contains one or more shaped holes through which the material is extruded. A cutting device, typically a rotating cutting device, cuts off pieces of extruded material to the desired length as they emerge from the die. One drawback of this technology is that when the cutting edge(s) of the rotating cutting device become dull, the production process must be shut down so that the cutting blade may be removed, sharpened and re-installed, or replaced with a new blade. Further, dull blades can lead to misshapen products. The cost of blades, along with the cost of lost production time when the process had to be stopped for the blades to be replaced can be high.
Typically, the tolerance between the blade and extruder die plate is very tight to ensure precise cutting of extruded product. The constant rotation of the blade can cause wear to the cutting edge of the blade, over time. This wear can be increased when the fastening devices holding the extruder die plate and cutting blade loosen even slightly. Because of the tight tolerance between the blade and the die plate, even a slight movement or deviation can cause the blade to wobble or torque, causing increased wear. In use, the die plate is under pressure from the extrudate pushing on the rear side of the plate, and can flex outwardly towards the cutting blades. This can cause greater contact between the die plate and the cutting blades than is desired, which can cause binding, and faster wearing of the blade edge, and increased possibility of breaking of the cutting blade. Additionally, if the die plate is made of a material that is not sufficiently flexible, the die plate can crack if the pressure from the extrudate is too great.
Depending on the material being extruded, when the blade contacts the edge of the material that is coming out of the die plate, there is increased resistance, and the blade can torque slightly. Because of the tight tolerances, when the blade and/or the die plate torque, they can come in contact with each other. This will cause additional wear on the blade and/or the die plate. The wear of the die plate is greater around the extrusion holes, causing misshapen extruded products, which can necessitate replacement of the die plate, as well as the accelerated wear on the cutting blade.
What is needed, therefore, is an apparatus for extruding shaped materials that enables cutting blades to have longer cutting life, and that prolongs the life of the die plate and maintains a quality of extruded product.